Complementary Metal-Oxide Semiconductor (CMOS) image sensors are solid-state imaging devices. CMOS image sensors are inexpensive to manufacture and have a small size, which reduces power consumption as compared to Charge-Coupled Device (CCD) image sensors employing high-voltage analog circuits consuming more power. Due to their improved performance and lower power consumption, CMOS image sensors are used in many electronic systems including portable devices, such as smart phones, digital cameras, etc.